Carbureter.



A. B. BROWNE.

CARBUREIER.

APPLICATION FILED AUG-21,1912.

Patented Dec. 12, WW.

2 SHEETS-SHEET I.

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A TI'ORNEYS WITNESSES 7 tit? tlltt BENT. JBROWNE, 01F BRANFORID, CONNECTICUT.

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Specification of Letters Patent.

Patented ee. 12, 1215.

Application filed August 21, 1912. Serial No. 716,150.

To all whom it may concern:

Be it known that T, ARTHUR BENJAMIN BnowNE, a citizen of the United States, residing at Branford, in the county of New Haven and State of Connecticut, have invented a new and useful Improvement in Carburetors; and I do hereby declare the Fig. 2 a vertical longitudinal sectional view of the same. Fig. 3 a vertical sectional view through the venturi. Fig. 4a sectional view on the line a;?; of Fig. 1.

This invention relates to an improvement in carbureters for supplying internal combustion motors with a combustible mixture of gas and air, and is an improvement on the carbureter shown and described in United States Patent No. 1,067,507, dated July 15, 1913, reissued August 4, 1914, No. 13,784.

Various objects of this invention are to form a jacketed carbureter body from asingle casting; to provide for regulating the amount of air which is admitted as the speed of the engine increases; to provide means whereby one size of carbureter may be made to answer the requirements of various sizes of engines; to prevent vibration of the auxiliary valve without recourse to the use of a dash pot or similar device; and to provide for supplying an excess'of gasolene during the moment of starting the engine; and the invention consists in the construction hereinafter described and particularly recited in the claims.

In carrying out my invention, I employ an inner shell or Venturi tube 2 opening at its upper end into a mixing chamber 3 and forming the primary inlet thereof, the outlet of said mixing chamber being controlled by the usual throttle 4. Surrounding the inner tube 2 is an outer shell or casing 5 cast integral with the inner shell and forming between the two a jacket 6 which is provided with an inlet 7 and an outlet 8. The inner and outer shellsare separated at the bottom to facilitate casting, and to close the opening between them, the lower end of the inner tube'extends beyond the lower end of the outer casing and is threaded to receive a nut-like closure 20 the inner face of which bears against the lower edge of the outer shell or casting and so as to close the chamber between'the two shells. Secured to the closure 20 is the usual priming cup 30. At one side is the usual float tank 9 which is preferably, and as herein shown, cast integral with the outer shell or casing 5. This float tank contains the usual float 10 operating a needle valve 11 which'controls the inflowvof the liquid into the tank from which it passes through achannel 12 to a nozzle 13 entering the Venturi tube 2, the opening in the nozzle being controlled by the usual needle valve 14. The usual means, extending above the float tank, is provided for raising the valve 11. To provide for clearing the float tank, I form a drainage opening 15 in the bottom and near its outer edge, this opening being connected by a passage 16 with the bottom of the tank. In the side wall of the float tank casing T form a vertical chamber 17 in which is located a screw valve 18 the lower end of which closes the discharge opening 15. This valve is provided at its upper end with a knurled head 19 by which the valve may be readily controlled, this head being easy of access.

Connected with, or preferably and as shown, formed integral with the body of the carbureter, is a cylindrical body 21 forming an auxiliary air chamber 22 connecting with the mixing chamber 3. This auxiliary chamber 22 is open at the top and in it is located a valve seat 23, and in the chamber is an imperforate cylindrical valve 24, the upper edge of which co-acts with curved walls surrounding the valve seat which are so proportioned that as the valve opens the opening produced by the travel of the valve is caused to vary in less thandirect proportion to the travel of the valve. The valve is preferably made cup-shaped, as shown, to prevent the momentum of the passing air from exercising undue influence on the opening of same. The lower end of the valve 24 forms the top wall of a vacuum chamber 25 opening through a passage 26 to the primary inlet, and in this chamber is a spring 27 normally acting to raise the valve against the seat 23. To overcome the communicationof sudden variations of pressure in the mixing chamber to the valve 24, the passage 26 is restricted, and this may be done by inserting a check valve in the passage. As herein shown this check valve consists of a 7 seat located in the passage and a ball 29 resting on said seat, which seat is preferably so formed that the ball will not completely close the passage. By the use of the check valve the restriction of'the passage of air from the mixing chamber to the vacuum chamber is greater in degree than the restriction of air from the vacuum chamber to the mixing chamber.

The air passes the mixing chamber 3 at greatly reduced velocity which is insufficient to carry all the particles of liquid fuel in suspension, and the liquid fuel accumulates on the walls of the mixing chamber. A portion of the fuel so deposited finds its way to the'vacuum chamber 25 from which it flows through the passage 26. The passage 26, therefore, also provides for the return of any liquid fuel thus collected in the vacuum chamber 25 to the primary inlet where it is again atomized by the high velocities therein. While the valve 24 fits the walls of the vacuum chamber 25 as closely as consistent with the movement of the valve therein, it cannot be made so tight that fuel accumulating on the walls of the chamber will not work through between the valve and the walls of the chamber.

When starting the engine, it is desirable to momentarily supply 'an excessive quantity of fuel, and for this purpose I provide a small passage such as the pipe 31 opening out of the float tank at a point slightly above the normal level of the fuel in the tank, and this pipe 31 leads to the priming cup 30 which is formed with a central depression 32. Leading from the priming cup 30 is a feed pipe 33 which extends to the throat of the venturi. When starting, the valve 11 will be raised to allow additional fuel to enter the tank so as to raise the level to the pipe 31 through which it will over flow promptly into the priming cup 30,

without the necessity of waiting for the flow to take place through the restricted area of the fuel nozzle. Upon cranking the engine, the fuel is drawn from the priming cup 30, through the feed pipe 33 by the diminished pressure in the throat of the venturi, supplying to the cylinders a mixture containing a slllofiicient amount of fuel to be readily igniti e.

' in this manner, this function of the appais, during the suction stroke of the motor which the apparatus is supplying, the velocity of the air passing through the Venturi tube 2 causes a certain reduction of pressure within said tube, resulting-inthe flow of liquid through the nozzle 13 and at As soon as the cup 30 is emptied ber 3. As the speed of the motor increases,

the increased velocity of air through the Venturi tube causes a proportional increase of pressure in the vacuum chamber, which in turn causes a proportional movement of the valve permitting the valve to open a proportional amount of its travel. The increase in the area of the opening afforded by the travel of the valve is less than in direct proportion to the said travel, in such degree as to cause such velocity through the primary opening as is necessary to maintain the mixture of fuel and air in definite proportions irrespective of the quantity of mixture supplied to the engine in a given time.

In order to maintain constant proportions of the mixture, given quantities of air must be admitted at definite velocities and to accomplish this it is necessary that the valve 24 should afford a certain definite area of opening for a given demand upon the carbureter and that this opening should be invariably maintained irrespective of barometric pressure and temperature. Any influences modifying a fixed relationship between the quantity of air passing through the carbureter and the velocity at which said air is admitted, change the proportions of the resulting mixture and the special form and arrangements of parts herein shown is that best adapted to maintain these conditions. As theproper area of the auxiliary opening at any given engine speed depends upon the piston displacement of the engine which the apparatus is supplying, in order that one size of carbureter may answer the requirements for a considerable range of engine sizes, I prefer to construct the valve seat 23 together with its surrounding curved walls, as a separate part as shown, so that if it be desired to supply a different size of engine, substitution may be made of a properly formed valve seat, Without disturbing the remainder of the apparatus.

I claim:

1. In a carbureter, the combination with an air chamber, of a spring controlled air inlet valve consisting of a cup-shaped cylinder located Within said chamber, in position to have its outer edge co-act with the walls of said chamber, which are so formed that the area of the opening produced by the travel of said valve varies in less than direct proportion to the travel of said valve.

2.- In a carbureter, the combination with an air chamber, of a valve seat detachably inserted into said chamber, and a spring controlled cup-shaped valve located within said chamber in position-to co-act with the naoaoer walls of the valve seat which are so formed that the area of opening produced by the travel of said valve, variesin less than direct proportion to the travel of said valve.

4:. In a carbureter, the combination with: the primary air-inlet thereof, of a combined auxiliary air-chamber and a vacuum cham ber located in line with each other, a valveseat located in the auxiliary air-chamber, an imperforate cylindricalvalve extended at one end into the said. air-chamber for ooaction with the valve-seat and having its opposite end extended into the said Vacuum chamber, a spring to normally close thesaid valve, and connection between the vacuumchamber and the main air-inlet of the carbureter, whereby a vacuum is created in the vacuum chamber for in part neutralizing the effect of the spring and permitting the valve to open, the said valve-seat being shaped so that the area of the opening produced by the movement of the valve in the said combined chambers will be less than a direct proportion to the movement of the valve.

5. In a carbureter, the combination with the mixing chamber thereof, of a vacuum chamber, a supplemental air-valve located in the said vacuum-chamber, and an airpassage between the bottom of the vacuumchamber and the said mixing-chamber, the said passage being of such a restricted area that sudden variations of pressure in the mixing-chamber are negligible in their eflect upon the" pressure in the vacuum-chamber.

6. In a carbureter, the combination with the mixing chamber thereof, of a vacuumchamber, a spring controlled air-valve located in the vacuum-chamber and operated by the vacuum therein, an air-passage connecting the vacuum-chamber and the mixing-chamber, and an automatic check-valve located in the said passage and operating to nullify suddenva'riations of pressure in, the mixing-chamber in their effect upon the vacuum in the vacuum-chamber so that the passage of airfrom the mixing-chamber to the vacuum-chamber is more restricted than the passage of air from the vacuum chamber to the mixing-chamber.

7. lln a carbureter, the combination With the mixing-chamber thereof, of a combined auxiliary air-chamber and vacuum-chamber opening into each other, a valve-seat located in the auxiliary air-chamber, a cup-shaped valve extending into the said air and vacuum chambers with its outer edge co-acting with the walls of said valve seat so that the area of the opening produced by the movement of the valve varies in less than a direct proportion to the travel of the valve, a spring for closing the valve, and a passage connecting the vacuum-chamber and the mixing-chamber and restricted so that sudden variations of pressure in the mixingchamber will be modified in their action upon the vacuum in the vacuum-chamber.

8. in a carbureter, the combination with the primary inlet and float tank, of a priming cu below the primary inlet, an overflow plpe leading from the said float tank to the said priming cup, and a feed pipe leading from said cup to the interior of the primary inlet.

In testimony whereof, I have signed this specification in the presence of two subscribing witnesses.

ARTHUR BENJ. Bnown'n Witnesses:

CLARA L. WEED, MALCOLM P. NICHOLS. 

